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Abstract:

A wheel axle suspension for suspending a round hollow axle (10) from a
vehicle comprises on both sides of the vehicle a trailing arm (1,41,51)
to which the axle (10) is attached. The trailing arm is hingedly
connected at the front to a bearing bracket (42) which is arranged on the
vehicle chassis (43). A pneumatic spring (44) is operational between the
trailing arm and the chassis. The axle body bears directly against a
contact region (5,45,55) of the trailing arm. The contact region is
essentially complementary to the outer contour of the axle body, wherein,
on that side of the axle body opposite the contact region, a support part
(20,46,56) is provided with a recess (21) for accommodating the axle. The
support part is clamped against the axle by means of clamping means
(23,24,47,48). At the location of the contact region, the trailing arm is
wider than in the region (2,41a, 52) which is situated immediately in
front thereof.

Claims:

1. A wheel axle suspension for suspending an axle body (10) of a wheel
axle from a vehicle, comprising on both sides of the vehicle a trailing
arm (1, 41, 51) which extends in the longitudinal direction of the
vehicle and to which the axle body (10) is attached, which trailing arm
(1, 41, 51) is hingedly connected at the front, viewed in the direction
of travel of the vehicle, to a bearing bracket (42) which is arranged on
the vehicle chassis (43), as well as a pneumatic spring (44) which is
operational between the trailing arm (1, 41, 42) and the chassis (43),
wherein the axle body (10), in the fitted position, bears directly
against a contact region (5, 45, 55) of the trailing arm (1, 41, 51),
which contact region (5, 45, 55) is essentially complementary to the
outer contour of the axle body (10), the trailing arm being clamped
against the axle body by means of clamping means (23, 24, 47, 48),
wherein the trailing arm (1, 41, 51) is wider at the location of at least
the front of the contact region (5, 45, 55) than in the region (2, 41a,
52) which is situated immediately in front thereof

2. The wheel axle suspension according to claim 1, wherein a support part
(20, 46, 56) is provided on that side of the axle body (10) which is
turned away from the contact region (5, 45, 55) of the trailing arm (1,
41, 51), and is provided with a recess (21) for accommodating the axle
body, the clamping means (23, 24, 47, 48) clamping the axle body between
the support part (20, 46, 56) and the contact region of the trailing arm.

3. Wheel The wheel axle suspension according to claim 1, wherein the axle
body is round and hollow in cross section.

4. The wheel axle suspension according to claim 1, wherein the axle body
has a substantially circular cross section at the location of the
clamping arrangement.

5. The wheel axle suspension according to claim 1, wherein the trailing
arm, at the location of the axle clamping arrangement, is provided with
one or more holes on both sides of the axle body for inserting clamping
bolts or the shanks of U-shaped clamping straps.

6. The wheel axle suspension according to claim 1, wherein the support
part surrounds the axle body over at least 180.degree. of its periphery.

7. The wheel axle suspension according to claim 1, wherein the trailing
arm is designed as a spring trailing arm.

8. The wheel axle suspension according to claim 7, wherein the trailing
arm is at least partially produced by forging.

9. The wheel axle suspension according to claim 1, wherein the portion of
the trailing arm which forms the contact region tapers towards the rear.

10. The wheel axle suspension according to claim 1, wherein the portion
of the trailing arm which forms the contact region, in top view, has an
approximately triangular shape, the greatest width of which is situated
at the front of said portion and the tip of the triangle being situated
at the rear of that portion.

11. The wheel axle suspension according to claim 10, wherein the support
part is provided with a securing arm for the pneumatic spring, and
wherein the axle body is clamped between the trailing arm and the support
part, and wherein the securing arm extends further towards the rear and
wherein the clamping means clamp the trailing arm and the support part
against the axle body.

12. The wheel axle suspension according to claim 11, wherein two holes
are provided near the wide front of that portion of the trailing arm
which forms the contact region, and a single hole is provided at the
narrower rear of said portion, for example in order to accommodate three
clamping bolts (or one U-shaped strap and one bolt).

13. A wheel axle suspension for suspending an axle body of a wheel axle
from a vehicle, comprising on both sides of the vehicle a trailing arm
(110) which extends in the longitudinal direction of the vehicle and to
which the axle body is attached, which trailing arm is hingedly connected
at the front, viewed in the direction of travel of the vehicle, to a
bearing bracket which is arranged on the vehicle chassis, as well as a
pneumatic spring which is operational between the trailing arm and the
chassis, wherein the axle body, in the fitted position, bears against a
contact region of the trailing arm, which contact region is essentially
complementary to the outer contour of the axle body, wherein a support
part is provided on that side of the axle body which is turned away from
the contact region, which support part is provided with a recess for
accommodating the axle body, which support part is clamped against the
axle body by means of clamping means, and wherein the trailing arm is
provided at the front of the contact region with two holes (120, 121)
through which the clamping means extend, wherein the trailing arm, at the
rear of the contact region, is provided with a single hole (122) through
which a clamping means, preferably the shank of a bolt, extends.

14. The wheel axle suspension according to claim 13, wherein the trailing
arm (110) is a spring trailing arm.

15. The wheel axle suspension according to claim 13, wherein the trailing
arm (110) is wider at the front of the contact region than at the rear of
the contact region.

16. The wheel axle suspension according to claim 14, wherein the spring
portion of the spring trailing arm (110) is narrower than at least the
front of the contact region.

17. The wheel axle suspension according to claim 13, wherein the portion
which forms the contact region (112) has a substantially triangular shape
when viewed from the top.

18. The wheel axle suspension according to claim 13, wherein the clamping
means are three bolts, the bolt shanks of which extend through the holes,
and with the bolt shank at the rear of the contact region having a larger
diameter than the bolt shanks at the front of the contact region.

19. The wheel axle suspension according to claim 13, wherein that portion
of the trailing arm which constitutes the axle clamping has a central rib
(124) on the side which is turned away from the axle body which extends
from the front of the contact region, between the two holes at said
front, in the direction towards the single hole at the rear of the
contact region, a depression (125, 126) being provided on either side of
this central rib in which, in each case, one of the holes (121, 122) at
the front is situated, with a further rib (124a, 124b) preferably being
present along each side edge of the respective portion which delimits the
depression on that side.

20. The wheel axle suspension according to claim 13, wherein the trailing
arm (110) is at least partially produced by forging, preferably from
spring steel.

21. A wheel axle suspension for suspending an axle body (10) of a wheel
axle from a vehicle, comprising a trailing arm (1, 41, 51) which extends
in the longitudinal direction of the vehicle and on both sides of the
vehicle and to which the axle body (10) is attached, which trailing arm
(1, 41, 51) is hingedly connected at the front, viewed in the direction
of travel of the vehicle, to a bearing bracket (42) which is arranged on
the vehicle chassis (43), as well as a pneumatic spring (44) which is
operational between the trailing arm (1, 41, 42) and the chassis (43),
wherein a support part (20, 46, 56) is provided on that side of the axle
body (10) which is turned away from the trailing arm (1, 41, 51), and is
provided with a recess (21) for accommodating the axle body, the clamping
means (23, 24, 47, 48) clamping the axle body of the wheel axle between
the support part (20, 46, 56) and the contact region of the trailing arm,
wherein furthermore an absorber attachment is provided which is provided
with one or more lips or a fork for attaching an absorber to the trailing
arm, wherein a separate absorber securing part (90) is provided which is
provided with one or more lips or a fork for hingedly attaching an eye of
a shock absorber, which absorber securing part is clamped between the
trailing arm and the support part in the fitted position.

22. A wheel axle suspension for suspending an axle body (10) of a wheel
axle from a vehicle, comprising a trailing arm (1, 41, 51) which extends
in the longitudinal direction of the vehicle and on both sides of the
vehicle and to which the axle body (10) is attached, which trailing arm
(1, 41, 51) is hingedly connected at the front, viewed in the direction
of travel of the vehicle, to a bearing bracket (42) which is arranged on
the vehicle chassis (43), as well as a pneumatic spring (44) which is
operational between the trailing arm (1, 41, 42) and the chassis (43),
wherein a support part (20, 46, 56) is provided on that side of the axle
body (10) which is turned away from the trailing arm (1, 41, 51), and is
provided with a recess (21) for accommodating the axle body, the clamping
means (23, 24, 47, 48) clamping the axle body of the wheel axle between
the support part (20, 46, 56) and the contact region of the trailing arm,
wherein furthermore an absorber attachment is provided which is provided
with one or more lips or a fork for attaching an absorber to the trailing
arm, wherein a separate absorber securing part with a bush (91) is
provided through which, in the fitted position, a shank of one of the
clamping means, for example a clamping bolt or clamping strap, extends,
by means of which clamping means the bush is clamped against the trailing
arm or support part, the bush being provided with one or more lips or a
fork (93) for hingedly attaching an eye of a shock absorber.

23. A wheel axle suspension for suspending an axle body (10) of a wheel
axle from a vehicle, comprising a trailing arm (1, 41, 51) which extends
in the longitudinal direction of the vehicle and on both sides of the
vehicle and to which the axle body (10) is attached, which trailing arm
(1, 41, 51) is hingedly connected at the front, viewed in the direction
of travel of the vehicle, to a bearing bracket (42) which is arranged on
the vehicle chassis (43), as well as a pneumatic spring (44) which is
operational between the trailing arm (1, 41, 42) and the chassis (43),
wherein a support part (20, 46, 56) is provided on that side of the axle
body (10) which is turned away from the trailing arm (1, 41, 51), and is
provided with a recess (21) for accommodating the axle body, the clamping
means (23, 24, 47, 48) clamping the axle body of the wheel axle between
the support part (20, 46, 56) and the contact region of the trailing arm,
wherein furthermore an absorber attachment is provided which is provided
with one or more lips or a fork for attaching an absorber to the trailing
arm, wherein the absorber attachment (25; 49) is integrally formed with
one of the clamping means, for example one clamping means is designed as
a bolt with a bolt shank and a bolt head, the bolt head being provided
with one or more lips or a fork for hingedly attaching an eye of a shock
absorber.

24. A wheel axle suspension for suspending an axle body of a wheel axle
from a vehicle, comprising a trailing arm which extends in the
longitudinal direction of the vehicle and to which the axle body is
attached, which trailing arm, in the direction of travel of the vehicle,
is hingedly connected at the front to a bearing bracket which is arranged
on the vehicle chassis, wherein furthermore an absorber attachment is
provided for attaching an absorber which absorbs the movement of the
trailing arm, which absorber has a telescopic body having an eye at each
end of the body, wherein the wheel axle suspension comprises a separate
absorber securing part (140) which is provided with one or more lips or a
fork for hingedly attaching an eye of a shock absorber, which absorber
securing part (140), in the fitted position, is directly connected to the
vehicle chassis.

25. The wheel axle suspension according to claim 24, wherein the absorber
securing part is provided with an integral bolt shank (142), preferably a
single integral bolt shank, which is inserted through an opening in the
chassis of the vehicle and secured by means of a nut (143).

26. An assembly for a wheel axle suspension for suspending an axle from a
vehicle, comprising: a trailing arm (51, 71) which, in use, extends in
the longitudinal direction of the vehicle and to which the axle can be
attached, wherein the trailing arm (51, 71) can be hingedly connected to
a bearing bracket which is attached to the vehicle chassis, which
trailing arm (51, 71) has a contact region (55, 75) against which an axle
body having a first outer diameter can bear directly, wherein the contact
region (55, 75) is substantially complementary to the outer contour of
the axle body having the respective outer diameter, a support part (56,
76) which, in use, can be attached on that side of the axle body which is
turned away from the contact region (55, 75) of the trailing arm, which
support part (56, 76) is provided with a recess (57, 77) for
accommodating the axle, and which support part (56, 76) is furthermore
provided with a securing arm (59, 769) which, in the fitted position,
extends to the rear from the support part (59, 769), which securing arm
(59, 769) is designed so that the underside of a pneumatic spring can be
fitted thereto, the top side of the pneumatic spring being attached to
the vehicle chassis, clamping means for clamping the contact region (55,
75) of the trailing arm (51, 71) and the support part (56, 76) against
the axle body, a shell part (60) which can be fitted between the contact
region (55, 75) of the trailing arm (51, 71) and an axle body, which
shell part (60) has an outer contact surface (62) which is designed to
bear in a fitting manner against the contact region which has a diameter
which is adapted to the first diameter and has an inner contact surface
(61) which is designed to bear against an axle body having a second
diameter, the second diameter being smaller than the first diameter.

27. A method for producing wheel axle suspensions for wheel axles having
axle bodies of different diameters, wherein use is made of the assembly
according to claim 26, wherein, based on the diameter of the axle body,
no shell part or a shell part (60) adapted to the diameter is fitted
between the axle body and the trailing arm.

28. The method according to claim 27, wherein different support parts
(56; 76) having a recess adapted to the different diameters of the axle
bodies are provided, with a support part being selected and fitted in the
wheel axle suspension based on the diameter of the respective axle body.

29. The method according to claim 27, wherein the trailing arm (51) is
produced by rolling and/or forging, and wherein the support part (56; 76)
is produced by casting or forging.

30. A method for producing a spring trailing arm designed for a
pneumatically sprung wheel axle suspension, preferably a wheel axle
suspension for suspending an axle body of a wheel axle from a vehicle,
comprising a trailing arm which extends in the longitudinal direction of
the vehicle and on both sides of the vehicle and to which the axle body
is attached, which trailing arm is hingedly connected at the front,
viewed in the direction of travel of the vehicle, to a bearing bracket
which is arranged on the vehicle chassis, as well as a pneumatic spring
which is operational between the trailing arm and the chassis, wherein
the trailing arm (41; 51; 71; 110; 150) is at least partially produced by
forging.

31. The method according to claim 30, wherein the trailing arm (41; 51;
71; 110; 150) is made of spring steel.

32. The method according to claim 30, wherein forging is carried out on a
rolled and/or cast semi-finished product.

33. The method according to claim 30, wherein the trailing arm, during
forging, comprises a projecting part which is suitable for holding the
semi-finished product during forging and which is removed after the
forging process.

34. The method according to claim 30, wherein the trailing arm on the
front end thereof is provided with a securing eye (111) which is formed
by forging, preferably in such a manner that the eye has a closed annular
body portion around the hole of the eye.

35. A method for producing a trailing arm for a wheel axle suspension for
suspending an axle body for a vehicle, wherein a securing eye is formed
on the trailing arm by means of which the trailing arm can be hingedly
connected on a bearing bracket on a vehicle chassis, wherein following
the formation of the securing eye (111), the trailing arm (110) is
twisted about the longitudinal axis of the trailing arm, so that the
securing eye (111) is rotated through an angle, said twisting preferably
taking place in a portion (114) of the trailing arm which adjoins the
securing eye.

36. The method according to claim 35, wherein the trailing arm is formed
from a semi-finished product having a width which is greater than the
thickness, wherein the securing eye (111) is then formed in a pre-forming
position, wherein the axis of the securing eye extends substantially
parallel to the thickness direction, following which the eye (111) is
moved to a desired position by twisting the trailing arm, preferably in a
portion (114) of the trailing arm which adjoins the securing eye.

37. The method according to claim 36, wherein the securing eye (111) is
rotated substantially through 90.degree. with respect to the pre-forming
position after the trailing arm has been twisted.

38. The method according to claim 35, wherein the trailing arm (110) is
at least partially produced by forging.

39. The method according to claim 35, wherein the securing eye (111) is
produced by forging, preferably in such a manner that the eye has a
closed annular body portion surrounding the hole of the eye.

40. The method according to claim 35, wherein the trailing arm, adjacent
to the securing eye, has a portion (114) which is to be twisted and has a
substantially round cross section, which region is twisted in order to
move the eye into the desired position.

41. The method according to claim 40, wherein the portion (114) to be
twisted and having a round cross section is produced by forging,
preferably at the same time as the forging of the securing eye.

42. The method according to claim 35, wherein the trailing arm, at least
the securing eye thereof and any portion adjacent thereto which is to be
twisted and has a round cross section, is formed by forging in a forging
device, wherein twisting takes place after forging using a twisting
device, when at least the portion of the trailing arm which is to be
twisted is hot, preferably still hot from forging, and wherein twisting
preferably takes place in a single uninterrupted twisting movement.

43. A trailing arm for a wheel axle suspension for suspending an axle
body of a wheel axle from a vehicle, which trailing arm has a securing
eye at the front end for attaching the trailing arm to the vehicle, for
example to a bearing bracket which is provided on the vehicle chassis,
for example using a hinge bolt, wherein the trailing arm (110), adjacent
to the securing eye (111), has a portion which has a substantially round
cross section (114), in particular a circular cross section.

44. The trailing arm according to claim 43, wherein the trailing arm
comprises a portion (113) having a substantially rectangular cross
section between the portion having a substantially round cross section
(114) and a portion which is designed for attaching the axle body.

45. The trailing arm according to claim 44, wherein the portion having
the substantially round cross section (114) merges smoothly with the
portion having the substantially rectangular cross section (113).

46. The trailing arm according to claim 43, wherein the trailing arm is a
spring trailing arm (110).

47. The trailing arm according to claim 45, wherein the portion having
the substantially rectangular cross section is the spring portion (113)
of the spring trailing arm.

48. The trailing arm according to claim 43, wherein the portion having a
substantially round cross section (114), and preferably also the securing
eye (111), is formed by means of forging, wherein, in the case of a
spring trailing arm, the spring portion (113) is preferably also formed
by forging.

49. The trailing arm according to claim 43, wherein the portion having
the substantially round cross section (114) is twisted in order to move
the eye into a desired position.

50. A method for producing a trailing arm according to claim 48, wherein
the portion (114) having a substantially round cross section, and
preferably also the securing eye, is formed by means of forging, wherein,
in the case of a spring trailing arm, the spring portion is preferably
also formed by forging.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is the National Stage of International Application
No. PCT/NL2008/000177, filed Jul. 18, 2008, which claims the benefit of
Netherlands Application Nos. 1034171, filed Jul. 20, 2007 and 1034756,
filed Nov. 23, 2007, the contents of all of which are incorporated by
reference herein.

FIELD OF THE INVENTION

[0002] The invention relates to the field of a wheel axle suspension for
suspending an axle body of a wheel axle from a vehicle, in particular a
road vehicle, such as a lorry or a lorry trailer.

[0003] In particular, the invention relates to the field in which a wheel
axle suspension, on each side of the vehicle, has a suspension arm which
extends substantially in the longitudinal direction of the vehicle,
called a "trailing arm" in the art, and to which the axle body is
attached, each trailing arm being hingedly connected at the front, viewed
in the direction of travel of the vehicle, to a bearing bracket which is
arranged on the vehicle chassis. In a known embodiment, a pneumatic
spring is arranged between the trailing arm and the chassis of such a
wheel axle suspension.

[0004] Trailing arms for wheel axle suspensions of this kind can
essentially be divided into two types: spring trailing arms (also
referred to as flexible trailing arms) and rigid trailing arms. In
practice, a resilient bush is used for connecting rigid trailing arms to
a bearing bracket which is mounted on the vehicle chassis, in which case
the resilient bush absorbs relative movements of the wheel axle
suspension. In the case of wheel axle suspensions which use spring
trailing arms, the majority of the relative movements are absorbed by the
deformation of a spring portion of the trailing arm itself. In this case,
the spring trailing arm is often produced in the form of a monolithic and
solid part from a suitable steel grade, in particular spring steel. The
spring portion is situated between the area where the wheel axle is
connected to the trailing arm and the front end of the trailing arm,
where the arm is hingedly attached to a bearing bracket. The different
operational principles of the trailing arms result in different
requirements imposed on the trailing arms. Spring trailing arms are
designed to be able to cope with relatively large deformations without
breaking This requirement also has consequences for the production of the
trailing arms.

[0005] The invention relates inter alia to the trailing arm of a wheel
axle suspension of this type, both with regard to the design of the
trailing arm and with regard to the method for the production of a
trailing arm of this type.

[0006] The invention also relates to the production of wheel axle
suspensions of this type, in particular the production of such wheel axle
suspensions for wheel axles having different diameters.

[0007] A first aspect of the invention relates to the contact of the axle
body and the trailing arm in the case of a wheel axle suspension.

[0008] A wheel axle suspension is disclosed in, for example, DE 296 15
286. With this known wheel axle suspension, the axle body is clamped
directly against a contact region of a spring trailing arm by means of a
clamping plate which is situated on that side of the axle body which is
turned away from the trailing arm, and by a pair of U-shaped clamping
straps extending around the trailing arm and through holes in the
clamping plate. At the location of the axle clamp, the axle body is
deformed to form a non-round contour with flattened regions which contact
the contact region of the trailing arm. Here, the spring trailing arm has
a constant width, that is to say, the contact region and the spring
portion have the same width.

BACKGROUND OF THE INVENTION

[0009] In order to save material, weight and space in the structure, the
bearing springs are generally designed to be as narrow as possible, with
the trailing arm still having a width and height which are such that the
rolling motions of the vehicle can still be absorbed to a sufficient
degree. In the case of the spring trailing arm from DE 296 15 286, this
results in the axle body which extends at right angles to the trailing
arm being only clamped in over a limited length of the axle body. As a
result thereof, the axle body is subjected to high loads locally, due to
the high clamping forces which are required to fix the axle. Particularly
with thin-walled tubular axle bodies, this is a problem as these axle
bodies, due to the great forces, are deformed significantly which
adversely affects their service life. It is known to increase the length
of the axle body which is clamped in by using an axle pad which is
arranged between the trailing arm and the axle body and is wider than the
trailing arm. Such a structure is shown, for example, in FIG. 7 of DE 296
15 286, but has the drawback that more parts are required which results
in a more complicated fitting.

[0010] It should be noted that US 2006/0163834 discloses a wheel axle
suspension having a rigid trailing arm which is produced by casting or
forging and is provided with a sleeve through which the axle body extends
in the fitted state. The sleeve may be formed as a single part, with the
axle body having to be pushed into the latter in the axial direction, but
the sleeve may also be made up of two halves which are welded to one
another by means of axial welding after the axle body has been placed
therein. The sleeve is wider than that part of the trailing arm which is
situated in front thereof. The sleeve is designed to be welded to the
axle body. To this end, the sleeve has openings in which a plug weld or
the like can be provided for connecting the sleeve to the axle body.

SUMMARY OF THE INVENTION

[0011] It is an object of the first aspect of the invention to provide an
improved wheel axle suspension.

[0012] This object is achieved, according to the first aspect of the
invention, by means of a wheel axle suspension according to the present
invention. The trailing arm is wider at the location of at least the
front of the contact region than in the region which is situated
immediately in front thereof.

[0013] In one embodiment as a spring trailing arm, the trailing arm at the
location of at least the front end of the contact region is wider than
the spring portion of the trailing arm, which is situated more to the
front. In practice, the spring trailing arm is usually provided with an
integrally formed securing eye and the spring portion is situated between
that securing eye and the contact region, the trailing arm having a
significantly greater stiffness at the location of the contact region
than the spring portion.

[0014] The first aspect of the invention makes it possible to make the
design the trailing arm lightweight, while still clamping a sufficient
length of the axle body to spread the load on the axle body resulting
from the clamping and thus preventing the axle body from being subjected
to locally excessive loads and to deformation, while not requiring any
additional components between the axle body and the trailing arm.

[0015] It has been found that the axle body is mainly loaded and deformed
at the front of the clamping arrangement. This makes it possible to taper
the portion of the trailing arm which forms the contact region towards
the rear, i.e. to reduce the width thereof towards the rear. At the front
of the clamping arrangement, the axle body is then clamped over a
sufficient length of the axle body, while the axle body is clamped over a
smaller length at the rear of the clamp. This results in a saving in
material and weight.

[0016] For example, the portion of the trailing arm which forms the
contact region for the axle body, in top view, has an approximately
triangular shape, the greatest width of which is situated at the front of
said portion and the tip of the triangle being situated at the rear of
that portion. This embodiment can be used in particular when the support
part is provided with a securing arm for the pneumatic spring, preferably
integrally formed with the support part, wherein the axle body is clamped
between the trailing arm and the support part, and wherein the securing
arm extends further towards the rear. In that case, for example, clamping
means are provided which clamp the trailing arm and the support part
against the axle body. For example, two holes are then provided near the
wide front of that portion of the trailing arm which forms the contact
region, and a single hole is provided at the narrower rear of said
portion, for example in order to accommodate three clamping bolts (or one
U-shaped strap and one bolt).

[0017] Preferably, the axle body has a substantially circular cross
section at the location of the axle clamping arrangement. Axle bodies
having a circular cross section are more capable of absorbing moments of
torsion than axles with a different cross section, for example a square
cross section. In addition, it is preferable to use a hollow axle body.

[0018] In a preferred embodiment, the support part surrounds the
preferably round and hollow axle body over at least 180° of its
periphery. As a result, the clamping force is distributed evenly over the
periphery of the axle body and the axle body is prevented from becoming
excessively deformed and deviating from a circular shape to an excessive
degree. As a result of this measure, relatively thin-walled axle bodies
can be used which in itself results in a weight saving of the vehicle.

[0019] In one possible embodiment, the support part is omitted and the
trailing arm, at the location of the axle clamping arrangement is
provided with holes on both sides of the axle, for inserting the shanks
of U-shaped clamping straps. As a result of this measure, it may be
possible to achieve a weight saving.

[0020] Preferably, the trailing arm is designed as a spring or flexible
trailing arm. The rolling motions about the longitudinal axis of the
vehicle are absorbed by these spring trailing arms.

[0021] In another possible embodiment, the trailing arm is designed as a
rigid arm. Such rigid arms are hingedly connected to the bearing bracket
by means of a resilient bush.

[0022] Preferably, the trailing arm and the axle body are locked with
respect to one another by means of a locking means. As a result of this
locking action, a rotation of the axle body with respect to the trailing
arm due to torsional forces is prevented. Preferably, the axle body or
trailing arm is provided with a projection at the location of the axle
clamping arrangement and the trailing arm or axle body, is provided with
a complementary recess for accommodating the projection.

[0023] If a support part is used, the support part may be provided with
recesses for accommodating at least a bend portion of U-shaped clamping
straps.

[0024] It is an object of a second aspect of the invention to improve, in
a pneumatically sprung wheel axle suspension, the attachment of the axle
body to the trailing arm by means of the clamping means and/or to provide
an alternative solution.

[0025] The second aspect of the invention provides a pneumatically sprung
wheel axle suspension according to. In this case, the portion of the
trailing arm which forms the contact region for the axle body has two
holes at the front of the contact region and one hole at the rear of the
contact region, with the clamping means extending through these holes.
This solution is based on the insight that the load on the axle body and
any deformation of the axle body primarily takes place at the front of
the clamping arrangement. In this case, the axle body is preferably
hollow and advantageously has a circular cross section.

[0026] The solution according to the second aspect of the invention makes
it possible to design the wheel axle suspension with fewer and/or smaller
clamping means compared to the prior art, which facilitates mounting and
can result in a saving on material and weight.

[0027] Preferably, the trailing arm is a spring trailing arm. In this
case, the portion between the part where the trailing arm is hingedly
connected to the bearing bracket and the contact region is the spring
portion.

[0028] Preferably, the trailing arm is wider at the front of the contact
region than at the rear of the contact region. As a result thereof, it is
possible to achieve a saving on material and thus weight as well.

[0029] In one possible embodiment, the contact region has a substantially
triangular shape when viewed from the top, in particular a shape which is
substantially similar to that of an equilateral triangle.

[0030] In one possible embodiment, the clamping means are three bolts, the
bolt shanks of which extend through the holes, with the bolt shank at the
rear of the contact region having a larger cross section than the bolt
shanks at the front of the contact region. As a result thereof, the cross
section of the clamping means can be adapted to the load, for example in
such a manner that the stresses in the clamping means are equal on both
sides of the contact region.

[0031] In order to save material and thus weight without significantly
reducing the strength of the trailing arm, it is possible to provide a
depression which extends from one of the two holes at the front of the
portion which forms the contact region in the direction of the hole at
the rear of said portion.

[0032] In an advantageous embodiment, that portion of the trailing arm
which forms the axle clamping arrangement has a central rib on the side
which is turned away from the axle body which extends from the front of
the portion which forms the contact region, between the two holes at said
front, in the direction towards the single hole at the rear, a depression
being provided on either side of this central rib wherein, in each case,
one of the holes at the front is situated, with a further rib preferably
being present along each side edge of the respective portion which
delimits the depression on that side.

[0033] Preferably, the trailing arm is at least partially produced by
forging. Preferably, at least the portion which forms the contact region
is produced by forging. As will be explained below, the entire trailing
arm is preferably produced by forging, with a securing eye at the front
of the trailing arm being brought into the intended position after
forging by twisting the trailing arm, if desired.

[0034] A third aspect of the invention relates to a wheel axle suspension,
wherein an absorber is also provided, in practice usually a shock
absorber having a telescopic body provided with mounting eyes on the ends
of the body.

[0035] It is an object of the third aspect of the invention to provide
improvements and/or to present alternatives for the attachment of such an
absorber to that side of the absorber turned towards the trailing arm.

[0036] In a first variant according to the third aspect of the invention,
a separate absorber securing part is provided which is provided with one
or more lips or a fork for hingedly attaching an eye of a shock absorber,
which absorber securing part is clamped between the trailing arm and the
support part in the fitted position.

[0037] Preferably, the absorber securing part has a rear concave surface
which, in the fitted position, contacts the axle body.

[0038] Preferably, the absorber securing part has one or more
through-holes through which in each case one leg of a clamping means
extends.

[0039] In a second variant according to the third aspect of the invention,
a separate absorber securing part with a bush is provided through which,
in the fitted position, a shank of one of the clamping means, for example
a clamping bolt or clamping strap, extends, by means of which clamping
means the bush is clamped against the trailing arm or support part, the
bush being provided with one or more lips or a fork for hingedly
attaching an eye of a shock absorber.

[0040] In a third variant according to the third aspect of the invention,
it is provided that the absorber attachment is integrally formed with one
of the clamping means, for example one clamping means is designed as a
bolt with a bolt shank and a bolt head, the bolt head being provided with
one or more lips or a fork for hingedly attaching an eye of a shock
absorber.

[0041] A fourth aspect of the invention relates to the attachment of a
possible absorber to the chassis. In practice, a shock absorber is
usually provided between the trailing arm and the chassis, with the
absorber usually having a telescopic body having an eye at each end of
the body for attaching the absorber to the trailing arm and the chassis.

[0042] According to the fourth aspect of the invention, a structure
having, among other things, a separate absorber securing part which is
provided with one or more lips or a fork for hingedly attaching an eye of
a shock absorber, which absorber securing part, in a fitted position, is
directly connected to the vehicle chassis. This has the advantage that
the forces are passed on directly to the vehicle chassis by the shock
absorber and do not pass via the bearing bracket. As a result thereof,
the bearing bracket can be optimized further for hingedly supporting the
trailing arm. Furthermore, the fitting of the bearing bracket can be
simplified if the shock absorber is no longer connected to the bearing
bracket.

[0043] In one preferred embodiment, the absorber securing part is provided
with an integral bolt shank, preferably a single integral bolt shank,
which is inserted through an opening in the chassis of the vehicle and
secured by means of a nut. This measure simplifies the fitting. In this
case, the absorber securing part can be used to replace the normal
bolt/nut connection, as a result of which the number of bolt/nut
connections remains the same.

[0044] A fifth aspect of the invention relates to the efficient production
of pneumatically sprung wheel axle suspensions, in particular wheel axle
suspensions for wheel axles with different cross-sectional dimensions.

[0045] In practice, hollow tubular wheel axles having a circular cross
section and an outer diameter of 127 mm are often used for lorries. For
trailers, hollow tubular wheel axles having a circular cross section and
an outer diameter of 146 mm are often used. Other diameters are also
known.

[0046] It is an object of the fifth aspect of the invention to make
efficient production of pneumatically sprung wheel axle suspensions
possible.

[0047] To this end, the fifth aspect of the invention provides an assembly
for a wheel axle suspension for suspending an axle from a vehicle.
According to this aspect, the assembly comprises a shell part which can
be fitted between the contact region of the trailing arm and the axle
body, which shell part has an outer contact surface which is designed to
bear in a fitting manner against the contact region which has a diameter
which is adapted to the first diameter and has an inner contact surface
which is designed to bear against an axle body having a second diameter,
the second diameter being smaller than the first diameter.

[0048] According to the fifth aspect of the invention, it is provided that
the trailing arm is produced for an axle body having a large outer
diameter, for example 146 mm, but that it can also be used for axle
bodies having a smaller diameter, for example 127 mm.

[0049] Preferably, with this aspect of the invention, the support part is
provided with a recess which is adapted to the outer diameter of the axle
body. In this manner, a universal trailing arm for axle bodies of
different diameters can be produced, while a specific support part and,
if desired, a specific shell part are produced for each variant
embodiment.

[0050] The fifth aspect of the invention also relates to a method for
producing wheel axle suspensions for wheel axles having axle bodies of
different diameters, wherein use is made of the abovementioned assembly,
wherein, based on the diameter of the axle body, no shell part or a shell
part adapted to the diameter is fitted between the axle body and the
trailing arm. In one preferred embodiment, different support parts having
a recess adapted to the different diameters of the axle bodies are
furthermore provided, with a support part being selected and fitted in
the wheel axle suspension based on the diameter of the respective axle
body.

[0051] A sixth aspect of the invention relates to the production of a
spring trailing arm for a pneumatically sprung wheel axle suspension.

[0052] As has already been mentioned, the trailing arms for such a wheel
axle suspension can be divided into two types: sprung and rigid trailing
arms. Rigid trailing arms are connected to a bearing bracket on a vehicle
chassis by means of a resilient bush, with the resilient bush absorbing
the relative movements of the wheel axle suspension. With wheel axle
suspensions which use spring arms, the majority of the relative movements
are absorbed by the deformation of a spring portion of the trailing arm
itself. This spring portion is situated between the area where the axle
is connected to the trailing arm and the front end of the arm, where the
arm is hingedly suspended from a bearing bracket. The various operational
principles result in different requirements being imposed on the trailing
arms. Spring trailing arms are designed to be able to cope with
relatively large deformations without breaking This requirement also has
consequences for the production of the trailing arms.

[0053] It is known to produce rigid structures which do not allow great
deformations by means of casting or forging. An example thereof is the
rigid trailing arm from US 2006/0163834. This trailing arm is of the
rigid type and is therefore only suitable for wheel axle suspensions
wherein the resilient bush absorbs the deformations. A drawback of these
wheel axle suspensions is the fact that these are less suitable for
absorbing rolling motions of the vehicle.

[0054] By tradition, spring trailing arms have a substantially rectangular
cross section and, according to the prior art, are always produced by
rolling. By deforming and kneading the material during the rolling
process, the trailing arm becomes resilient, thus preventing the trailing
arm from breaking in the event of relatively small deformations. However,
rolling has the drawback that passing a (semi-finished) product between
two rollers results in the cross section of the product being
unambiguously determined in one direction and no variation in cross
section is possible, in principle, viewed in the longitudinal direction
of the trailing arm.

[0055] Some variation in the cross section is still possible if the
(semi-finished) product is not passed between the two rollers in its
entirety, but is pulled back in time. Another option would be to move the
rollers towards one another or further apart while the product is being
passed through. Apart from the fact that this requires a complicated
control unit for the process, the shape of the trailing arm is largely
limited due to the production process.

[0056] Some variation in cross section also occurs because the rolling
process usually only determines the thickness with sufficient accuracy.
The dimensions in the other two directions, i.e. the longitudinal
direction and the width direction, cannot be controlled in principle. All
this is dependent on the starting material. Different starting materials
lead to different end products, so that there is insufficient control
over the three-dimensional dimensions of the product.

[0057] It is an object of the sixth aspect of the invention to provide an
improved and/or alternative manufacturing method for the spring trailing
arm.

[0058] According to the sixth aspect of the invention, the spring trailing
arm is at least partially produced by forging. This has the advantage
that the shape of the trailing arm is not limited to such a large degree
by the manufacturing process. This offers more freedom in terms of design
and can lead to savings on material, weight and space.

[0059] If there is more freedom in terms of design this offers the
possibility of optimizing the design of a spring trailing arm further.
Optimization of the trailing arm is desirable if, for example, the
trailing arm is not only subjected to flexural loads, but, for example,
also to torsional loads as a result of, inter alia, the rolling motion of
the vehicle. By now using forging during the manufacturing process, more
shapes are possible for the trailing arm.

[0060] A greater degree of freedom of design offers the advantage that
parts of the trailing arm can be optimized for the function they perform.
As a result, the trailing arm can be made more lightweight and still be
sufficiently strong locally to absorb the loads to which it is subjected.
Ultimately, the freedom of design leads to savings in material, weight
and/or space.

[0061] Preferably, the trailing arm is made of spring steel.

[0062] Preferably, the trailing arm is made in its entirety in a single
operation from the starting material. In other words, the trailing arm is
preferably formed by one blow of the forging device.

[0063] With the invention, it is possible to carry out the forging on a
rolled and/or cast semi-finished product. In this case, the semi-finished
product formed by rolling and/or casting serves as a base for the
finished product formed by forging. This ensures that there is less loss
of material during the forging and simplifies the forging process.

[0064] In one possible embodiment, the semi-finished product comprises a
projecting part. This projecting part is suitable for holding the
semi-finished product and orienting it during forging. After the forging
process, this part is removed. However, it is also possible for the
projecting part by which the trailing arm is held not to be removed
during forging, but for it to be part of the finished trailing arm. All
this depends on the design of the trailing arm. An advantage thereof is
the fact that even less material is required to manufacture the trailing
arm.

[0065] After forging, the trailing arm is preferably hardened by means of
a hardening process. This hardening process is preferably performed on
the surface of the trailing arm.

[0066] A seventh aspect of the invention relates to a method for producing
a trailing arm for a wheel axle suspension, preferably a pneumatically
sprung wheel axle suspension, wherein the trailing arm has a securing eye
at the front end. As is known, the trailing arm is in practice connected
to a bearing bracket by means of the securing eye and a pin (if desired
designed as a bolt) inserted through the eye, which bearing bracket is in
turn attached to the chassis of the vehicle.

[0067] It is an object of the seventh aspect of the invention to provide
an improved and/or alternative manufacturing process for such a trailing
arm.

[0068] The seventh aspect of the invention provides a method, wherein
method--following the formation of the securing eye--the trailing arm is
twisted about the longitudinal axis of the trailing arm, so that the
securing eye is rotated through an angle, said twisting preferably taking
place in a portion of the trailing arm which adjoins the securing eye.

[0069] The seventh aspect of the invention can advantageously be used for
producing spring trailing arms of suitable steel.

[0070] An advantage of this method is the fact that the orientation of the
securing eye can be adapted to the desired position in the wheel axle
suspension.

[0071] A wheel axle is sometimes produced in the form of a bend in order
to make space, for example, for a cardan shaft. In most cases, a trailing
arm is then attached to a horizontal part of the wheel axle corresponding
to a horizontally oriented hinge pin of the securing eye. By twisting the
trailing arm and orienting the securing eye in this manner, the trailing
arm can be attached to any part of the wheel axle, it being possible for
the hinge pin to remain oriented horizontally in the fitted position (as
is usual), while allowing the trailing arm to be attached to an oblique
part of the wheel axle. In this case, any rotation can be used,
preferably 1° to 90°, but larger rotations, such as for
example 120°, are also possible.

[0072] A second advantage offered by this method relates to the
manufacturing process. The invention makes it possible for the securing
eye to be oriented differently during a step of the manufacturing process
than in the finished wheel axle suspension. By now carrying out the
manufacturing process with the eye at a different orientation and
subsequently twisting the trailing arm, preferably in a defined region,
which preferably has a round cross section, in order to reach the final
orientation of the securing eye, the manufacturing process can be
optimized.

[0073] Preferably, the trailing arm is, at least partially, produced by
forging.

[0074] In one embodiment, the trailing arm is formed from a semi-finished
product, the width being greater than the thickness of the semi-finished
product. The securing eye is then, possibly in one blow, formed using a
forging hammer in a pre-forming position of the eye, with the axis of the
hole in the eye at that point in time still being in the thickness
direction, that is to say at right angles to the width of the trailing
arm, in particular when the spring trailing arm has a spring portion
which has a substantially rectangular cross section. The forging hammer
preferably also moves in said thickness direction, i.e. in fact at right
angles to the principal plane of the trailing arm. The securing eye is
then moved to the desired position by twisting a part of the trailing
arm. The desired position of the eye will usually be rotated through
90° with respect to the pre-forming position, with the axis of the
hole in the eye, after twisting, running substantially parallel to the
width of the trailing arm.

[0075] When forming the securing eye, the forging hammer is possibly
designed as the complementary portion of the half of the securing eye to
be formed. On the other side of the forging hammer, an anvil is provided
which is complementary with the other half of the securing eye to be
formed. By now placing the portion to be formed between the forging
hammer and the anvil, the securing eye can be formed, preferably with one
blow.

[0076] Forming the trailing arm with the securing eye by forging offers
the advantage that the forming process is quick compared to, for example,
a prior art process using rollers wherein the eye has to be formed later
by means of bending. This is advantageous for the time of passage of the
trailing arm to be produced. In addition, forging makes it possible to
produce an eye having a closed annular body portion surrounding the hole
of the eye. This results in a strong eye and, compared to bending a
rolled portion of the trailing arm, as is used in the prior art with
spring trailing arms, has the advantage that there is no interruption in
the material at a seam and no welding operation is required in order to
close this seam.

[0077] It is conceivable that several blows of the forging hammer are
required in order to form the securing eye. This is the case, for
example, when the shape of the securing eye is relatively complicated.

[0078] Preferably, the securing eye formed by forging does not require any
shape-defining finishing, but with more complicated shapes and/or more
stringent requirements with regard to tolerances, it is expected that one
or more, preferably simple finishing operations may be required to
produce the final shape of the securing eye.

[0079] In one advantageous embodiment, a portion having a substantially
round cross section, in particular a circular cross section is formed,
adjacent to the securing eye, in such a manner that during twisting of
the arm, the deformation takes place completely or at least substantially
within the portion having the substantially round cross section.

[0080] Preferably, the trailing arm, or at least the front end thereof
with the securing eye and the portion having a round cross section which
is provided, if desired, and adjoins the securing eye, is formed in its
entirety by forging in a forging device. In this case, the eye is
preferably formed from a portion of the trailing arm which was
originally--prior to forging--circular, with the hole being formed in the
eye by forging. If desired, a hole could already be present in the
originally circular portion.

[0081] Preferably, twisting takes place after forging using a twisting
device, when at least the portion of the trailing arm which is to be
twisted is hot, in practice red-hot, preferably still hot from forging
and/or as a result of suitable heating of the part to be twisted.
Preferably, twisting takes place in a single uninterrupted twisting
movement until the desired position of the securing eye has been reached.

[0082] An eighth aspect of the invention relates to a wheel axle
suspension having, among other things, a trailing arm having a portion
which has a substantially round cross section (114), in particular a
circular cross section. In this case, there is provided a trailing arm
for a wheel axle suspension for suspending an axle body of a wheel axle
from a vehicle, which trailing arm has a securing eye at a front end for
attaching the trailing arm to the vehicle, for example to a bearing
bracket which is provided on the vehicle chassis, for example using a
hinge bolt. Adjacent to the securing eye, the trailing arm has a portion
which has a substantially round cross section, in particular a circular
cross section.

[0083] One advantage of this round cross section is the fact that stresses
in the material resulting from torsion due to, for example, a rolling
motion of the vehicle, are distributed virtually evenly along the
periphery of the cross section, where the deformation and the stress is
greatest.

[0084] Another advantage of this aspect of the invention becomes clear in
combination with the twisting of the trailing arm in order to orient the
securing eye. When the portion of the trailing arm which is adjacent to
the securing eye has a substantially round cross section before the
securing eye is twisted and the deformation during twisting takes place
completely or substantially in the portion having the substantially round
cross section, this not only results in uniform stresses along the
periphery of the cross section, but the shape of the portion of the
trailing arm which is adjacent to the securing eye is also substantially
identical to the situation prior to twisting and there is less
superfluous material.

[0085] In one embodiment, the trailing arm comprises at least one portion
having a substantially rectangular cross section between the securing eye
and the arm region where the axle body is connected to the trailing arm.
This has the advantage that the stiffness of the trailing arm can be
optimized in various directions. This is particularly advantageous if the
trailing arm also has to absorb transverse forces, for example when the
vehicle goes around a bend.

[0086] In order to prevent peak stresses or stress concentrations as much
as possible, the portion having the substantially round cross section
then preferably merges smoothly with the portion having the substantially
rectangular cross section.

[0087] The eighth aspect of the invention can be used with both sprung and
rigid trailing arms. If the trailing arm is a spring trailing arm and has
a portion which has a substantially rectangular cross section, this
portion is preferably the spring portion.

[0088] In one embodiment, the trailing arm, or at least the front part
thereof, is produced by means of forging, preferably according to one or
more aspects of the invention.

[0089] It will be clear to those skilled in the art that the forged
trailing arms according to the various aspects and preferred embodiments
of the invention, as is already customary for pneumatically sprung wheel
axle suspensions for lorries, trailers and the like, are preferably
designed as monolithic and solid parts made from a suitable steel grade,
particularly spring steel in the case of spring trailing arms.

[0090] It will be clear to those skilled in the art that the various
aspects of the invention can be used separately, but also in all kinds of
different combinations. Non-limiting examples of the aspects and of
combinations of these aspects of the invention will be explained below
with reference to the drawing.

[0091] The invention also relates to a vehicle provided with a wheel axle
suspension according to one or more aspects of the invention and/or a
trailing arm according to one or more aspects of the invention, the wheel
axle suspension preferably being pneumatically sprung. The vehicle is for
example a lorry or a lorry trailer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0092] In the drawings:

[0093] FIG. 1 shows a perspective view at an angle from above of a
preferred embodiment of a trailing arm for a wheel axle suspension
according to the invention;

[0094]FIG. 2 shows a perspective view at an angle from below of the
trailing arm from FIG. 1;

[0095] FIG. 3 shows a side view of an axle clamping arrangement wherein a
round axle is clamped against the trailing arm from FIG. 1;

[0096] FIG. 4 shows a side view of a wheel axle suspension according to
the invention with an alternative embodiment of a trailing arm;

[0097] FIG. 5 shows a perspective view of another alternative embodiment
of a trailing arm for a wheel axle suspension according to the invention;

[0098] FIG. 6 shows a side view of a shell part which can be used with the
trailing arm from FIG. 5;

[0099] FIG. 7 shows a side view of a trailing arm for an alternative wheel
axle suspension according to the invention;

[0100]FIG. 8 shows a side view of yet another alternative wheel axle
suspension according to the invention;

[0101] FIG. 9 shows a top and side view of an alternative exemplary
embodiment of a trailing arm for a wheel axle suspension according to the
invention;

[0102] FIG. 10 shows a side view of a bearing bracket and vehicle chassis
with an absorber securing part according to the invention fitted thereto;
and

[0103] FIG. 11 shows a highly diagrammatic view of a trailing arm with a
securing eye according to the invention in a pre-forming position and a
desired position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0104] FIG. 1 and FIG. 2 show a spring trailing arm 1, which is also
referred to in the art as a flexible trailing arm. The trailing arm 1 has
a spring portion 2 which is provided at the front, viewed in the
direction of travel of the vehicle, with a securing eye 3. The trailing
arm 1 can, by means of a hinge bolt, be hingedly connected to a bearing
bracket which is provided on the underside of a vehicle chassis. The
bearing bracket or equivalent supporting structure can also be integral
with the vehicle chassis.

[0105] Following on from the spring portion 2 of the trailing arm 1, a
curved portion 4 is formed, which curved portion 4 has a concave contact
surface 5 which is directed downward in the example shown. Following on
from the curved portion 4, an end portion 6 is formed which is intended
for fitting a pneumatic spring thereto. The illustrated trailing arm 1
has a shape which is referred to in the field as "gooseneck".

[0106] The spring portion 2 of this arm 1 has a substantially rectangular
cross section having a width and a thickness, the width being greater
than the thickness. The spring portion 2 may be produced by rolling, but
could also be produced by forging. The curved portion 4 is preferably
produced by forging.

[0107] In this case, four bore holes 7 are provided in the curved portion
4 which serve to insert clamping bolts. The bore holes 7 are recessed
with respect to the top surface of the curved portion.

[0108] FIG. 3 shows how an axle body 10 which is designed as a relatively
thin-walled, substantially round tube is clamped against the trailing arm
1. Such a tubular axle body has, for example, an outer diameter of 146 mm
and a wall thickness which is between 7 and 9 mm. Such an axle body can
be deformed in the radial direction relatively easily.

[0109] FIG. 3 shows that the axle clamping arrangement here comprises a
support part 20, as is preferred in combination with a hollow axle body.
The support part 20 has a recess 21 in which a part of the axle body 10
is accommodated. In the fitted position, a part of the periphery of the
axle body 10 is clamped against the inner wall 22 of the recess 21, which
inner wall 22 is complementary with the outer contour of the axle body
10. The support part 20 is clamped against the underside of the axle body
10 by means of bolts 23, having a bolt head 23a and a bolt shank 23b,
which are inserted into bore holes 7 in the trailing arm 1, and by means
of nuts 24.

[0110] As can clearly be seen in FIG. 3, more than 180° of the
periphery of the axle body 10 bears against the inner wall 22 of the
support part 20. The inner wall 22 of the support part 20 and the contact
surface 5 of the curved portion 4 of the trailing arm 1 surround
virtually the entire periphery of the axle body 10, as FIG. 3 clearly
illustrates. This is advantageous when clamping relatively thin-walled
axles since the load is omnidirectional, as a result of which the axle
body 10 remains round at the location of the clamping arrangement.

[0111] In this example, the curved portion 4 of the trailing arm 1 is
wider than the spring portion 2. The width of the spring portion 2 is
such that the rolling motion of the vehicle can be withstood. The curved
portion 4 is wider, resulting in a lower surface pressure on the axle
body, in particular when absorbing transverse forces. The round hollow
axles can be clamped directly against the trailing arm, without the use
of an axle pad or another fitting piece. It is known from the prior art
to arrange an axle pad between the axle and the trailing arm, which axle
pad is arranged in a fitting manner against the axle body on that side
which is turned towards the axle and is arranged in a fitting manner
against the trailing arm on that side which is turned towards the
trailing arm.

[0112] In the context of the first aspect of the invention, however,
provision is made for a so-called galvanized plate to be fitted between
the axle body and the trailing arm. This relatively thin galvanized plate
offers cathodic protection against stress corrosion of the trailing arm,
but does not serve any purpose in connection with arranging the axle body
and the trailing arm together in a fitting manner.

[0113] FIG. 3 shows a possible embodiment of the front clamping bolts 23.
The bolt heads 23a of the front clamping bolts 23 are provided with
securing lips 25 to which a shock absorber 26 is hingedly attached. The
securing lips 25 extend from the bolt head 23a upwards and to the front
at an angle. It is also possible for a single bolt head to be provided
with several lips or with a fork, for example in order to arrange the eye
of a shock absorber therebetween.

[0114] The axle body 10 is preferably locked against rotation with respect
to the trailing arm 1. In theory, there are several options for locking
Preferably, locking is effected by providing a recess or depression in
the contact surface 5 and to provide a projection on the axle body 10,
for example in the form of a welded-on spline 11, as is illustrated in
NL1022395. In addition to locking against a movement of the axle with
respect to the trailing arm resulting from the action of torsional
forces, for example due to the wheels of the vehicle braking, the
projection and the recess furthermore also form a positioning means for
axially correctly positioning the axle in the correct manner during
assembly. Another possibility of locking against rotation is to provide a
projection, for example in the form of a segment of a sphere, on the
contact surface 5. The axle may be provided with a recess or depression
as is illustrated in EP 1 334 848 in the name of Schmitz Cargobull AG.

[0115] In addition to the possibility of locking the axle body 10 with
respect to the trailing arm, an embodiment is also conceivable wherein
the axle body 10 is locked in a similar way with respect to the support
part 20. A variant involving locking of the axle body 10 with respect to
both the trailing arm and the support part is also possible. The same
applies to the embodiments which have been illustrated in FIGS. 4 and 5.

[0116] FIG. 4 shows a wheel axle suspension for suspending a round hollow
axle 10 from a vehicle. The wheel axle suspension comprises on both sides
of the vehicle a trailing arm 41 which extends in the longitudinal
direction and to which the axle 10 is attached. The trailing arm 41 is
hingedly connected at the front, viewed in the direction of travel of the
vehicle, to a bearing bracket 42 which is arranged on the underside of
the vehicle chassis 43. At the rear, a pneumatic spring 44 is fitted
between the trailing arm 41 and the chassis 43.

[0117] In the assembled state, the axle body 10 bears directly against a
contact region 45 of the trailing arm 41. The shape of the contact region
41 is essentially complementary to the outer contour of the axle body 10.
On the side of the axle body 10 which is turned away from the contact
region 45 of the trailing arm 41, a support part 46 is present which is
provided with a recess for accommodating the axle 10. The trailing arm
and the support part 46 are clamped against the axle body 10 by means of
clamping bolts 47 and nuts 48.

[0118] In this example, the front clamping bolts 47 are provided on their
bolt heads with a securing lip 49 to which an end of a shock absorber 401
is attached. The other end of the shock absorber 401 is connected to the
bearing bracket 42 or directly to the chassis.

[0119] On the support part 46, an additional arm 461 is fitted which
extends to the front and upwards at an angle from the support part 46 and
is connected to the trailing arm 41 on the end which is turned away from
the support part. The connection between the additional arm 461 and the
trailing arm 41 serves to reduce the load on the trailing arm 41. The
additional arm 461 can be designed as a spring.

[0120] FIG. 5 shows an alternative embodiment of a trailing arm. On the
front end which is to be fitted to the bearing bracket, the trailing arm
51 has a securing eye 53, by means of which the trailing arm 51 can be
attached to the bearing bracket by means of a hinge bolt. The trailing
arm 51 has a spring portion 52. Adjacent to the spring portion 52 of the
trailing arm 51, a curved portion 54 is formed, which curved portion 54
has a concave contact surface 55 which is facing upwards in the
illustrated example. The curved portion 54 tapers towards the spring
portion in the width direction.

[0121] FIG. 5 furthermore shows a support part 56 which is positioned
opposite the curved portion and has a recess 57 for accommodating a part
of the periphery of the axle body.

[0122] For the sake of clarity of the drawing, the axle body has been
omitted in this FIG. 5. In the fitted position, a part of the periphery
of the axle body bears against the inner wall 58 of the recess 57, which
inner wall 58 is complementary to the outer contour of the axle body. The
support part 56 is clamped against the top side of the axle body by means
of bolts (not illustrated). To this end, the support part is provided
with securing holes 561.

[0123] As can clearly be seen in FIG. 5, more than 180° of the
periphery of the axle body lies against the inner wall 58 of the support
part 56.

[0124] In this example, the inner wall 58 of the support part 56 and the
contact surface 55 of the curved portion 54 of the trailing arm 51
surround virtually the entire periphery of the axle body 10, as FIG. 5
clearly shows. This is advantageous when clamping relatively thin-walled
axles since the load is then omnidirectional, as a result of which the
axle body 10 remains round at the location of the clamp. Incidentally, it
is also conceivable for the curved portion of the trailing arm to
surround the periphery of the axle body over more than 180°.

[0125] The support part 56 is provided with a securing arm 59, which in
this case is integrally formed with the support part, which arm 59, in
the fitted position, extends from the support part 56 to the rear. The
securing arm 59 is designed so that the underside of a pneumatic spring
(not shown) can be fitted thereto. The top side of the pneumatic spring
is attached to the vehicle chassis. Thus, the pneumatic spring in this
case acts on the hingedly connected trailing arm 51 via the support part
56.

[0126] In this example, the support part 56 is provided with two securing
lips 562 at the top side which extend upwards and to the front at an
angle. In the fitted position, a securing eye of a shock absorber is
arranged between the securing lips 562, which securing eye is hingedly
connected to the securing lips 562 by means of a bolt.

[0127] It is also possible to omit the securing lips 562 and instead use,
for example, the bolts 23 shown in FIG. 3 and having a bolt head 23a
which is provided with a securing lip 25.

[0128] In practice, axle bodies with different outer diameters are used.
Thus, trailers often use an axle body with an outer diameter of 146 mm,
while lorries for example use an axle tube of 127 mm. As has been
described above, according to one aspect of the invention, the curved
portion 54 with the concave contact surface 55 of the trailing arm 51 may
be designed to bear directly against an axle body having a specific
diameter, for example 146 mm or 127 mm.

[0129] According to one aspect of the invention, the trailing arm 51 is
produced for a large outer diameter of the axle body, for example 146 mm,
and can then also be used for axle bodies having a smaller diameter, for
example 127 mm. According to one aspect of the invention, this becomes
possible by arranging a shell part 60 (see FIG. 6) between the curved
portion and the axle body, which shell part 60 has an inner contact
surface 61 having an inner diameter which corresponds to the outer
diameter of the axle body, and has an outer contact surface 62 having an
outer diameter which can be arranged in a fitting manner against the
contact surface 55 of the curved portion 54 of the trailing arm 51.

[0130] The shell part 60 is preferably produced by casting. According to
this aspect of the invention, it is also possible for the support part 56
to be provided with a recess 57 which is adapted to the outer diameter of
the axle body.

[0131] In one possible embodiment, the contact surface 55 of the curved
portion 54 of the trailing arm 51 is adapted to an axle tube having an
outer diameter of 146 mm. In the curved portion 54, the outer contact
surface 61 of a shell part 60 is arranged against the contact surface 55
of the curved portion 54 of the trailing arm 51, which shell part 60 has
an inner contact surface 61 having an inner diameter of 127 mm. The
associated support part 56 has a recess 57 with an inner diameter of 127
mm.

[0132] In addition to the recess 57, it is also possible for the shape and
length of the arm 59 of the support part 56 to be adapted to the specific
variant of the wheel axle suspension. In this manner, a universal
trailing arm 51 can be produced which is suitable for various variant
embodiments of wheel axle suspensions, whereas one specific support part
56 is produced for each variant embodiment. This makes it possible to
produce the trailing arm 51 in large numbers which reduces the production
costs per trailing arm as the production line only has to be designed to
manufacture one single trailing arm 51. This is particularly advantageous
if the trailing arm 51 is produced by means of relatively expensive
processing steps, such as rolling and/or forging, which will, according
to the invention, often be the case when producing flexible trailing
arms.

[0133] The support part 56 is preferably produced in several variants,
depending on the variant embodiments, in particular diameters, of the
specific wheel axle suspensions.

[0134] Preferably, the support part 56 with the integrally formed arm 59
is produced by forging or casting, in which case it should be pointed out
that casting is less expensive than forging in the case of relatively
small production numbers.

[0135] With the embodiment from FIG. 5, a locking against rotation is
preferably provided between the support part 56 and the axle body, in
particular when a shell part 60 is used.

[0136] FIG. 7 shows a part of another embodiment of a wheel axle
suspension according to the invention. The wheel axle suspension
comprises a trailing arm 71 which is similar to the trailing arm 51 which
is shown in FIG. 5. At the end which is to be fitted to the front, the
trailing arm 71 has a securing eye 73 with which the trailing arm 71 can
be attached to a bearing bracket by means of a hinge bolt. The trailing
arm 71 has a spring portion 72. Adjacent to the spring portion 72 of the
trailing arm 71, a curved portion 74 is formed, which curved portion 74
has an upwardly directed concave contact surface 75. The curved portion
74 here has a greater width than the spring portion 72.

[0137] FIG. 7 furthermore shows a support part 76 which is positioned
opposite the curved portion and has a recess 77 for accommodating a part
of the periphery of the axle body 10. In the fitted position, a part of
the periphery of the axle body 10 is clamped against the inner wall 78 of
the recess 77, which inner wall 78 is complementary to the outer contour
of the axle body.

[0138] In this example, the support part 76 is clamped against the top
side of the axle body 10 by means of U-shaped clamping straps 80. In this
example, the top side of the support part 76 is provided with recesses 79
which extend essentially in the transverse direction and at least
partially accommodate the bend of the U shape. The downwardly extending
legs of the clamping straps 80 are situated along the sides of the
support part 76. Using clamping straps 80 instead of bolts (cf. FIGS. 5
and 7) has the advantage that the stretch length increases and the loss
of prestress is prevented more effectively.

[0139] A separate absorber securing part 90 is clamped at the front of the
axle body 10, between the front end of the support part 76, that is to
say where the front clamping strap 80 surrounds the support part 76, and
the trailing arm 71, at the location of the transition between the spring
portion 72 thereof and the curved portion 74 thereof.

[0140] In this example, the absorber securing part 90 has a rear concave
surface 91 which, in the fitted position, bears against the axle body 10.
In this example, the absorber securing part 90 has a few through-holes
through which the legs of the front U-shaped clamping strap 79 extend.
When the nuts 81 on the legs of the clamping straps 80 are tightened, the
absorber securing part 90 is clamped securely.

[0141] As can be seen in FIG. 7, approximately 180° of the
periphery of the axle body 10 bears against the inner wall 78 of the
support part 76. The inner wall 78 of the support part 76, that part of
the absorber securing part 90 which is turned towards the axle body 10,
and the contact surface 75 of the curved portion 74 of the trailing arm
71 surround virtually the entire periphery of the axle body 10, as FIG. 7
clearly shows. This is advantageous when clamping relatively thin-walled
axles, since the load is then omnidirectional, as a result of which the
axle body 10 remains round at the location of the clamping arrangement.

[0142] In this example, the front of the absorber securing part 90 is
provided with two securing lips 82 which extend upwards and to the front
at an angle. Each securing lip 82 is provided with a bore hole 83 through
which a bolt (not shown) extends in the fitted position. In the fitted
position, a securing eye of a shock absorber is situated between the
securing lips 82, which securing eye is hingedly connected to the
securing lips 82 by means of said bolt.

[0143] Similar to the support part 56, the support part 76 is provided
with a securing arm 769, which extends from the support part 76 to the
rear in the fitted position. The securing arm 769 is designed so that the
underside of a pneumatic spring (not shown) can be fitted thereto. The
top side of the pneumatic spring is attached to the vehicle chassis.
Thus, the pneumatic spring in this case acts on the hingedly connected
trailing arm 71 via the support part 76.

[0144] The embodiment from FIG. 7 also offers the possibility of using a
shell part 60, as has been described above with reference to FIGS. 5 and
6.

[0145]FIG. 8 shows a variant of the wheel axle suspension from FIG. 5.
The wheel axle suspension comprises a trailing arm 51 which substantially
corresponds to the trailing arm 51 which is shown in FIG. 5 and has
already been described above. The support part 56 is connected to the
curved portion 54 by means of bolts. An extension bush 91 is in each case
placed on the support part 56, above the front securing holes 561. The
front bolts 92 extend through this extension bush 91 and, in the fitted
position, the bolt head 92a is on the end side on the top side of the
extension bush 91. Preferably, that side of the extension bush 91 which
is turned to the front (viewed in the direction of travel of the vehicle)
is provided with a securing lip 93 having a bore hole 94. In the fitted
position, a hinge bolt is inserted into bore hole 94 in order to hingedly
attach an eye of a shock absorber to the lips 93. The use of an extension
bush 91 means that bolts 92 having a longer bolt length have to be used,
which offers the advantage that the stretch length increases and the loss
of prestress is prevented more effectively. An extension bush could also
be used with the rear clamping bolts, which would mean that longer bolts
would have to be used there as well and the stretch length increases. An
extension bush 91 can, if desired, also be designed without an absorber
securing lip 93 in order to achieve that advantage, which is regarded as
a further aspect of the invention.

[0146] FIG. 9 shows two views of a trailing arm 110 according to the
invention. FIG. 9A shows a top view of a spring trailing arm 110
comprising a securing eye 111, a curved portion which forms the contact
region 112 which can accommodate the axle clamp, and a spring portion 113
between these two parts. In the fitted position, the securing eye 111 is
attached to a bearing bracket (not shown). The securing eye 111 is at the
front of the trailing arm 110 and the portion which forms the contact
region 112 is situated, in this example, at the rear of the trailing arm
110.

[0147] Holes are provided on both sides of the contact region 112. Two
holes 120, 121 at the front of the contact region 112, and one hole 122
at the rear of the contact region 112. Clamping bolts or the shanks of
U-shaped clamping straps are inserted through these holes 120-122 in
order to clamp the trailing arm 110 to an axle body (not shown). Other
clamping means are also possible.

[0148] This example clearly shows that the trailing arm 110, at the
location of the contact region 112, is wider at the front of the contact
region 112 than in the region which is situated in front thereof (in the
direction of the securing eye 111) and the rear of the contact region 112
of the trailing arm 110. This measure creates a large contact surface in
the area where the load is highest, i.e. at the front of the contact
region, using a minimal amount of material, so that the axle body is not
undesirably deformed as a result of being clamped.

[0149] In this example, depressions 125, 126 have also been provided on
the outside of that portion of the trailing arm which forms the contact
region 112, with depression 125 extending from hole 120 in the direction
of hole 122, and depression 126 extending from hole 121 in the direction
of hole 122.

[0150] As can be seen, that portion of the trailing arm which forms the
axle clamping has, on that side which is turned away from the axle body,
a central rib 124 which extends from the front of the contact region,
between the two holes 120, 121 on said front, in the direction of the
single hole 122 at the rear of the contact region. On either side of this
central rib 124, there are depressions 125, 126, wherein in each case one
of the holes at the front is provided.

[0151] As is preferred, a further rib 124a, 124b is provided along each
side edge of the respective portion and delimits the depression on that
side.

[0152] The embodiment which has been illustrated and described above
provides a saving on material while the portion which forms the contact
region 112 is sufficiently strong.

[0153] In this exemplary embodiment, flat surface portions 127-129 are
provided round the holes 120-122. This make it possible for a bolt head
or nut to bear against the trailing arm 110 in a neat manner and to
transfer the clamping forces onto the trailing arm 110 in an effective
manner at relatively low peak stresses. In one variant, it is possible to
select the dimensions of the holes and associated clamping means
(clamping bolts or straps) in such a manner that clamping of the axle
body leads to uniform stresses in the clamping means.

[0154]FIG. 9b shows the spring trailing arm 110 from FIG. 9A in side
view. The two views, FIG. 9A and FIG. 9b together, clearly show that the
trailing arm has a portion 114 which is adjacent to the eye 111 and has a
substantially round cross section. If the trailing arm 110 is now
subjected to a torsional load, this results in virtually uniform
deformations and stresses along the periphery of the portion 114.

[0155] It is also possible to twist the arm 110 in the region 114 during
production of the trailing arm in order to adjust the position of the eye
111 to that required for fitting the trailing arm in the wheel axle
suspension. No significant change in shape of the portion 114 can be
observed during this twisting operation.

[0156] It is possible for the securing eye 111 to be formed in a different
position during a manufacturing process, such as forging, after which it
is, for example, turned by a quarter turn to a desired position and thus
assumes the position illustrated in FIGS. 9A and 9B. In this context, see
also FIGS. 11A and 11B. The advantage thereof is that this makes it
easier to form the securing eye 111 during the manufacturing process, in
other words fewer forming steps or less complicated forming steps are
required, following which the arm 110 only has to be twisted locally.

[0157] It is possible to produce the trailing arm 110 in a single
operation by forging. Preferably, the eye is also forged and this may
render finishing of the hole of the eye 111 superfluous.

[0158] Preferably, the eye 111 is forged in such a manner that after
forging the eye has a closed annular body portion surrounding the hole of
the eye, resulting in an eye of great strength.

[0159] It should be noted that, for example, a trailing arm 51 which is
illustrated in FIG. 5 can also be formed by forging. In this case, only
the hole in the eye 53 which is at right angles to the direction of the
forging direction (from top to bottom), has to be provided by a finishing
operation, for example boring.

[0160] Between portion 114 and the portion which forms the contact region
112, the spring portion 113 is present, which in this example has a
substantially rectangular cross section. As a result, the trailing arm
110 has different stiffness in different directions, which is
advantageous, for example, if the trailing arm 110 is also subjected to
transverse loads.

[0161] In this example, portion 114 merges smoothly with the spring
portion having the substantially rectangular cross section. This prevents
peak stresses in the material.

[0162] The shape of the trailing arm 110 is such that it can be produced
in its entirety by forging. Mainly the portion which forms the contact
region 112, the front portion 114 and the securing eye 111 are
pre-eminently suitable to be formed by forging and are a good example of
the additional freedom of design for each portion of the arm compared to
the prior-art spring trailing arms which are produced only by means of
rolling.

[0163] FIG. 10 shows a bearing bracket 130 which is connected by means of
bolt/nut connections to vehicle chassis 131, in this case a longitudinal
member of the chassis. In this example, the bearing bracket consists of
two plates, each of which is connected to the longitudinal member by
means of bolt/nut connections 132. In addition, part of an absorber 135
which is known per se can be seen, which usually has a telescopic body
with a securing eye 136 at each end. The absorber securing part 140 is
made of metal and has one or more lips or a fork 141 for attaching the
eye of the absorber. Said one or more lips may be at an angle, for
example approximately in line with the axis of the absorber. The securing
part 140 furthermore has an integral bolt shank 142, in this example a
single bolt shank, as is preferred. An opening has been drilled in the
vehicle chassis, in this case close to the bearing bracket, through which
the bolt shank extends. A nut 143 is screwed onto the bolt shank. The
advantage is now that the forces are passed directly to the vehicle
chassis by the shock absorber, resulting in less stringent requirements
being placed on the bearing bracket and thus leading to an improved
design.

[0165] Eye 151 is now in the pre-forming position, that is to say the
position in which eye 151 is formed. Forming has in this case taken place
from the top downwards, preferably by means of a forging device.

[0166] After the eye 151 has been formed, eye 151 can still be rotated
into a desired position. An example of a desired position is illustrated
in FIG. 11B, in which arrow T indicates the rotation of the eye 151. The
rotation of the eye 151 has been carried out by twisting the trailing arm
in the adjacent front portion 154. In this example, the eye 151 is
rotated a quarter turn, but other rotations between 1° and
90°, for example 45°, are also possible. It is also
possible to rotate the eye by more than 90°, for example by
120°.

[0167] As a result of the round cross section of the front portion 154, no
or hardly any change in shape can be seen after twisting. Twisting could
also take place in a front portion having a different cross section, for
example a rectangular cross section.

[0168] It should be noted that the invention is not limited to the
specific examples illustrated in the drawing. The person skilled in the
art will easily be able to think of variations and combinations of
elements from the different exemplary embodiments illustrated and these
are deemed to fall within the scope of the invention.

Patent applications by Derk Geert Aalderink, Laren NL

Patent applications by Geert Everts, Dalfsen NL

Patent applications by Hans Bramer, Eerbeek NL

Patent applications by Harm Damkot, Zutphen NL

Patent applications by WEWELER NEDERLAND B.V.

Patent applications in class Horizontal and transverse pivot axis

Patent applications in all subclasses Horizontal and transverse pivot axis